How Is Cannabis Tested for Residual Solvents?

Smoking dried flower isn’t the only way to harness the therapeutic benefits of cannabis, with medical cannabis manufacturers using solvents to extract cannabinoids such as CBD and THC. Once extracted, the cannabinoids can be easily blended into tinctures, topical oils, edibles and other products.

Ethanol, butane, benzene, acetone and propane are some of the most common solvents used to extract cannabinoids. While solvents are a useful and effective way to extract cannabinoids, traces can remain in the final product and cause health issues for consumers. This makes residual solvent analysis an important stage of medical cannabis testing.

Testing for residual solvents

Headspace (HS) Gas Chromatography (GC) coupled with Mass Spectrometry (MS) is one of the most useful techniques to test for residual solvents in cannabis products. The use of multiple techniques helps to improve the accuracy of results and eliminate the risk of false positives. Capable of detecting even the smallest traces of residual solvents, HS/GC/MS allows medical cannabis companies to meet strict regulatory standards and limits enforced by different countries, as well as individual states and territories. More importantly, residual solvent analysis ensures medical cannabis products, including concentrates, distillates, extracts and edibles, are free from toxins and safe to consume.

“The major benefit of this approach is that headspace is a fast, simple, accurate and precise technique that allows the components of interest (e.g. residual solvents and terpenes) to be introduced into the analytical system,” reads a study published by scientific solutions company, PerkinElmer.

The benefits of a multifaceted approach to testing

Sample preparation is minimal, which allows scientists and lab technicians to focus on other tasks. As well as generating fast and accurate results, HS/GC/MS has the scope to identify unknown residual solvents that haven’t been identified as target compounds. This improves results and contributes to the development of safer, purer medical cannabis products.  

“The non-volatile matrix components remain in the sample vial and do not enter the GC, which results in a mostly maintenance free system, and faster analysis time. In addition, the technique is mature and already has been accepted for quantitation in several regulatory industries including pharmaceutical forensics, environmental and food, where its results have routinely stood up to scrutiny in a court of law.”

A closer look at medical cannabis analysis

Residual solvents aren’t the only contaminant found in medical cannabis, with mould, mildew, yeast, bacteria and fungi also a concern. Find out more about the advanced scientific methods used to detect for microorganisms and mycotoxins, including PCR testing and petri film analysis, in ‘Medical Cannabis - Testing, Analysis & Identification’.